From c7bbc056a92476b3b3d70a8df7cc746ac5d56de7 Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov Date: Thu, 26 Mar 2009 18:26:40 -0700 Subject: USB: musb: bugfixes for multi-packet TXDMA support We really want to use DMA mode 1 for all multi-packet transfers; that's one IRQ on DMA completion, instead of one per packet. There is an important issue with such transfers, especially on the host side: when such transfers end with a full-size packet, we must defer musb_dma_completion() calls until the FIFO empties. Else we report URB completions too soon, and may clobber data in the FIFO fifo when writing the next packet (losing data). The Inventra DMA support uses DMA mode 1, but it ignores that issue. The CPPI DMA support uses mode 0, but doesn't handle its TXPKTRDY interrupts quite right either; it can get stale "packet ready" interrupts, and report transfer completion too early using slightly different code paths, also losing data. So I'm solving it in a generic way -- by adding a sort of the "interrupt filter" into musb_host_tx(), catching these cases where a DMA completion IRQ doesn't suffice and removing some needlessly controller-specific logic. When a TXDMA interrupt happens and DMA request mode 1 is active, that filter resets to mode 0 and defers URB completion processing until TXPKTRDY, unless the FIFO is already empty. Related filtering logic in Inventra and CPPI code gets removed. Since it should be competely safe now to use the DMA request mode 1 for host side transfers with the CPPI DMA controller, set it in musb_h_tx_dma_start() ... now renamed (and shared). [ dbrownell@users.sourceforge.net: don't introduce more CamElCase; use more concise explanations ] Signed-off-by: Sergei Shtylyov Cc: Felipe Balbi Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/cppi_dma.c | 22 +--------------------- 1 file changed, 1 insertion(+), 21 deletions(-) (limited to 'drivers/usb/musb/cppi_dma.c') diff --git a/drivers/usb/musb/cppi_dma.c b/drivers/usb/musb/cppi_dma.c index 569ef0fed0f..30e24891ed6 100644 --- a/drivers/usb/musb/cppi_dma.c +++ b/drivers/usb/musb/cppi_dma.c @@ -1228,27 +1228,7 @@ void cppi_completion(struct musb *musb, u32 rx, u32 tx) hw_ep = tx_ch->hw_ep; - /* Peripheral role never repurposes the - * endpoint, so immediate completion is - * safe. Host role waits for the fifo - * to empty (TXPKTRDY irq) before going - * to the next queued bulk transfer. - */ - if (is_host_active(cppi->musb)) { -#if 0 - /* WORKAROUND because we may - * not always get TXKPTRDY ... - */ - int csr; - - csr = musb_readw(hw_ep->regs, - MUSB_TXCSR); - if (csr & MUSB_TXCSR_TXPKTRDY) -#endif - completed = false; - } - if (completed) - musb_dma_completion(musb, index + 1, 1); + musb_dma_completion(musb, index + 1, 1); } else { /* Bigger transfer than we could fit in -- cgit v1.2.3 From 6b6e97107f12f3a9f7b5b43a6c3b94409240bcff Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov Date: Thu, 26 Mar 2009 18:29:19 -0700 Subject: USB: musb: fix isochronous TXDMA (take 2) Multi-frame isochronous TX URBs transfers in DMA mode never complete with CPPI DMA because musb_host_tx() doesn't restart DMA on the second frame, only emitting a debug message. With Inventra DMA they complete, but in PIO mode. To fix: - Factor out programming of the DMA transfer from musb_ep_program() into musb_tx_dma_program(); - Reorder the code at the end of musb_host_tx() to facilitate the fallback to PIO iff DMA fails; - Handle the buffer offset consistently for both PIO and DMA modes; - Add an argument to musb_ep_program() for the same reason (it only worked correctly with non-zero offset of the first frame in PIO mode); - Set the completed isochronous frame descriptor's 'actual_length' and 'status' fields correctly in DMA mode. Also, since CPPI reportedly doesn't like sending isochronous packets in the RNDIS mode, change the criterion for this mode to be used only for multi-packet transfers. (There's no need for that mode in the single-packet case anyway.) [ dbrownell@users.sourceforge.net: split comment paragraph into bullet list, shrink patch delta, style tweaks ] Signed-off-by: Pavel Kiryukhin Signed-off-by: Sergei Shtylyov Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/cppi_dma.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/usb/musb/cppi_dma.c') diff --git a/drivers/usb/musb/cppi_dma.c b/drivers/usb/musb/cppi_dma.c index 30e24891ed6..1976e9b4180 100644 --- a/drivers/usb/musb/cppi_dma.c +++ b/drivers/usb/musb/cppi_dma.c @@ -579,6 +579,7 @@ cppi_next_tx_segment(struct musb *musb, struct cppi_channel *tx) * trigger the "send a ZLP?" confusion. */ rndis = (maxpacket & 0x3f) == 0 + && length > maxpacket && length < 0xffff && (length % maxpacket) != 0; -- cgit v1.2.3